Integrated circuits (IC) are often used for wireless applications that include radio frequency (RF) devices and RF antennae. Frequency-related characteristics of an RF antenna are a function of the antenna's geometry and the physical properties of the antenna's components.
Antenna performance is sometimes gauged by an S11 parameter (also referred to as the reflection coefficient or power loss of the antenna), which indicates the amount of power returned by the antenna at an antenna input. Because an antenna typically has low internal losses, increased return losses usually correspond to increased radiation power.